Separating admin’s functionality to admin’s dashboard or integrating it to the regular users’ appearance

Could you please help me to choose between the options below?

• splitting admin's view of the web application to a regular user's dashboard and admin's dashboard
• having the single appearance for both admins and users but with some functionality visible for admins only

The workflows of admins and regular users are very different in our application, and I cannot decide whether admins should have the so called "User dashboard" with the relatively small number of activities available both for users and admins, and the "Admin dashboard" with the administrative only functionality. OR whether we should integrate admin's functionality into the regular user's appearance?